A Non-Contact Measurement System for the Range of Motion of the Hand

Abstract

An accurate and standardised tool to measure the active range of motion (ROM) of the hand is essential to any progressive assessment scenario in hand therapy practice. Goniometers are widely used in clinical settings for measuring the ROM of the hand. However, such measurements have limitations with regard to inter-rater and intra-rater reliability and involve direct physical contact with the hand, possibly increasing the risk of transmitting infections. The system proposed in this paper is the first non-contact measurement system utilising Intel Perceptual Technology and a Senz3D Camera for measuring phalangeal joint angles. To enhance the accuracy of the system, we developed a new approach to achieve the total active movement without measuring three joint angles individually. An equation between the actual spacial position and measurement value of the proximal inter-phalangeal joint was established through the measurement values of the total active movement, so that its actual position can be inferred. Verified by computer simulations, experimental results demonstrated a significant improvement in the calculation of the total active movement and successfully recovered the actual position of the proximal inter-phalangeal joint angles. A trial that was conducted to examine the clinical applicability of the system involving 40 healthy subjects confirmed the practicability and consistency in the proposed system. The time efficiency conveyed a stronger argument for this system to replace the current practice of using goniometers.

Hand neuro-motor characterization and motor intention decoding in Duchenne muscular dystrophy

“…Minimum and maximum active joint angles measured with Leap motion sensor and goniometer are compared using Bland-Altman plots and quantified by the mean difference and limits of agreement. Compared to previous similar studies [100], we avoided the use of Intraclass Correlation Coefficient (ICC) analysis. Our choice was motivated by the fact that there are no standard values for acceptable reliability using ICC [107] and that we had low variability in maximum flexion and extension angles between our participants, which disables the use of correlational analysis.…”

“…However, goniometry is the current clinical standard, and there is a plethora of studies related to measurements, protocols and different goniometers . Moreover, comparable studies evaluated new and existing sensors and measurement protocols against the goniometer, reporting promising results and significant reduction in measurement time, yet asking for further improvements in measurements protocols [100], [103], [109].…”

“…However, most of these instruments are expensive, take a lot of time to setup or are difficult to don and doff by people with hand deformities or severe muscle weakness, like in DMD. Pham et al developed a non-contact camera-based system that showed very promising results for the tracking of the finger MCP, PIP and DIP joints [100]. However, the price of that camera is still relatively high, and the proposed system is not currently commercially available.…”

“…Furthermore, it is a low-cost solution and it can minimize significantly measurement time since more than one joint can be measured simultaneously. It has been indicated that due to internal constraints of hand angles estimation, the leap is not a promising sensory modality for clinical practice [100]. However, a recent study showed promising results for the finger MCP joints using the Leap motion sensor [103].…”

Advanced face and gesture recognition for visual HMI

“…The Creative Senz3D device (see provides additional information about the hand location, but not skeletal information. HMI applications using this sensor include rehabilitation solutions as the one presented in [37], which measures the active range of the hand motion. Other rehabilitation solution introduces a system to improve the movement of the upper extremity [38].…”